From mboxrd@z Thu Jan  1 00:00:00 1970
From: lm@mcvoy.com (Larry McVoy)
Date: Tue, 26 Sep 2017 19:02:14 -0700
Subject: [TUHS] UNIX of choice these days?
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On Tue, Sep 26, 2017 at 09:37:13PM -0400, Chet Ramey wrote:
> On 9/26/17 8:58 PM, Dave Horsfall wrote:
> > On Tue, 26 Sep 2017, Grant Taylor wrote:
> > 
> >>> Exactly; why 255 of all things?
> >>
> >> High order of 8 bits??? (Assuming low order starts at 0.)
> > 
> > Yeah, but still doesn't answer the question, application-wise.?? I'm gonna
> > guess (without digging through the source) that it's a "dup2(0, 255)*" or
> > something, to "save" a copy of stdin/out/err for some obscure reason.
> 
> I already answered this.

OK, I'm gonna be that guy because I've learned when I ask, I learn.  

You answered but I didn't get any insight.  Why have an extra fd talking
to the tty?  bash has 0, 1, 2 talking to it.   If it were redirected 
would it have 255 pointing to some random tty?  I don't get the reason
for the extra fd.